Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it?
Copper is less reactive. So, when it is added to zinc sulphate solution, it doesn’t displace zinc from the salt... View Article
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Oxygen is returned to the atmosphere mainly by (a) burning of fossil fuel (b) respiration (c) photosynthesis (d) fungi
c) photosynthesis Explanation Oxygen is returned to the atmosphere mainly by photosynthesis.According to the earth’s history, oxygen gas was first... View Article
The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue. (True or False)
True Lining of blood vessels, lung alveoli and kidney tubules are all made of squamous and cuboidal epithelial tissues. The lining... View Article
Stages in the lifecycle of silkworm are given below. Write them in sequential order: pupa, silkworm, egg, silk moth.
c) Silk moth → egg → silkworm → pupa Silk is a natural fibre and was amongst the earliest fibres... View Article
Middle zone is the hottest zone of a flame. (True or False). Also write the false statements in their correct form.
False – outer zone is the hottest zone of a flame. Explanation The substances that vaporize while burning produces the... View Article
Look at Fig. and suggest in which of the vessels A,B, C or D the rate of evaporation will be the highest? Explain.
(c) In vessel The rate of evaporation increases with the increase in surface area and wind speed. The surface areas... View Article
Which one of the following nutrients is not available in fertilizers? (a) Nitrogen (b) Phosphorus (c) Iron (d) Potassium
c) Iron Explanation Iron is a nutrient that is not available in fertilizers. Fertilizers are chemical substances supplied to the... View Article
Which among the following is considered as the cleanest fuel? (a) cow dung cake (b) petrol (c) kerosene (d) hydrogen gas
Hydrogen gas is considered as the cleanest fuel because when hydrogen burns in air, it produces nothing but water vapour.... View Article
Name the practice followed for large scale rearing of farm animals. What facilities are provided to farm animals?
The process of domestication of animals and their rearing is known as animal husbandry. This process is used to increase... View Article
Draw the diagram of the alimentary canal of man and label the following parts. Mouth, Oesophagus, Stomach, Intestine
Buccal Cavity: It is the entry site for the food to the digestive system. Food is breakdown into simpler molecules... View Article
One of the following factors does not lead to soil formation in nature (a) the sun (b) water (c) wind (d) polythene bags
d) Polythene bag Explanation Polythene bags are not involved in soil formation. However, plastic bags are threat to environment, because... View Article
The water conducting tissue generally present in gymnosperm is (a) vessels (b) sieve tube (c) tracheids (d) xylem fibres
c) Tracheids Gymnosperms do not have vessels in their xylem. Water conducting tissues present in them are tracheids. They do... View Article
The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called___.
This phenomenon of change of a liquid into vapours at any temperature below its boiling point is called evaporation. Explanation... View Article
The substances which have very ________________ ignition temperature and can easily catch fire with a flame are called __________ substances.
The substances which have very low ignition temperature and can easily catch fire with a flame are called Inflammable substances.... View Article
Which of the following tools would a farmer use to remove weeds from the field? (a) Hoe (c) Axe (b) Plough (d) Cultivator
Hoe It is one of the oldest tools of agriculture, a digging implement consisting of a blade set at right... View Article
Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
In the environment, the percentage of the gases like oxygen, nitrogen and carbon dioxide is maintained by their cyclic flow.... View Article
Hard calcium carbonate structures are used as skeleton by (a) Echinodermata (b) Protochordata (c) Arthropoda (d) Nematoda
a) Echinodermata Explanation The body wall of Echinodermata is covered with spiny, hard, calcareous (calcium carbonate) plates (ossicles) that form... View Article
Rate of evaporation of an aqueous solution decreases with increase in humidity. Comment on the following statement.
If humidity is high, then air is already saturated with water vapours, i.e., it has a lot of water vapours.... View Article
Mention any two features each that are seen in boys and girls each to distinguish them from each other at puberty.
Changes that are seen in girls at the time of puberty Voice becomes thin Breasts enlarge Hips become rounded Hairs... View Article
In desert plants, the rate of water loss gets reduced due to the presence of (a) cuticle (b) stomata (c) lignin (d) suberin
(a) Cuticle Cuticle is a protective, hydrophobia waxy covering produced by epidermal cells of leaves, young shoots and other aerial... View Article
